Flank Steak with Grilled Guacamole Salad

Name: Flank Steak with Grilled Guacamole Salad
Yield: Serves 4
Cuisine: Southwest (Tex-Mex)
Ingredients: 1 (1½-pound), flank steak, trimmed; 6 tablespoons, extra-virgin olive oil, divided; 5 teaspoons, kosher salt, divided; 1 tablespoon, ground cumin; 1½ teaspoons, pepper, divided; 1 teaspoon, grated lime zest, plus 2 limes, halved; 1 , red onion, sliced into ½-inch-thick rounds; 10 ounces, cherry tomatoes; 2 , avocados, halved and pitted; 1 , jalapeño chile